The present invention relates generally to systems for detecting objects, and, more particularly, relates to photodetector systems and automatically actuated devices utilizing such systems.
It is desirable to have lids on waste containers to contain unpleasant sights and odors, and to protect against contamination from objects therein. Various waste containers with hand-operated lids have been developed, but suffer from inconvenience in use and risk of contamination when touched. Foot-operated designs minimize contamination risk, but are also often inconvenient or bothersome to use. Users of both hand and foot operated waste containers may be occupied with multiple tasks, or be situated in an inconvenient position, and not have a free hand or foot to operate the container lid.
Automatic cans of two general types have been developed. One type uses a proximity detector (e.g., pressure-sensitive mat or photoelectric detector) to sense the presence of a user in the vicinity of the container and actuate motor-driven door(s) to open. Doors generally close after a predetermined time period of non-detection. This type of automatic can is readily prone to false alarms from passing objects or persons.
The second type of automatic trash container has a physical xe2x80x98bayxe2x80x99, which objects must enter prior to passing through the automatic door of the container. The bay has one or more infrared beam emitters and detectors. Objects in the bay reflect beams of the infrared light zone and cause the motor-actuated door to open. The walls of the bay shield against detection of objects outside the bay.
Elimination of false alarms is improved with this type, but xe2x80x98false negativesxe2x80x99, or the non-detection of objects in the bay, is possible if objects are situated outside the zone.
Additionally, the requirement for an inner bay compromises the automatic waste container""s ability to contain contaminating objects and noxious emissions to the cants shielded interior. The inner periphery of the bay, which may become contaminated, is exposed. It is difficult to avoid this condition when a shielded photoelectric detection zone is created in front of an opening. The zone must be offset some distance from the door by an exposed physical structure so the door can be opened before incoming objects make contact. For the user to pause while the door opens is inconvenient, so the comfortable zone offset distance is significant.
What is required is an automatic waste container that creates a non-physical detection zone, with a precisely controlled configuration to minimize false triggerings. For a can with an upward-facing opening, the detection zone should be a continuous, vertical xe2x80x98curtainxe2x80x99 matching the profile of the opening periphery, so only objects crossing the virtual, vertically-extended boundary of the opening activate the can. This configuration reduces the detection zone boundary to a logical minimum, thereby substantially decreasing unintentional triggerings. It is also desirable for the height of the detection zone to be adjustable by the user in order to avoid false triggerings by the presence of nearby structure, objects or zones of activity situated in the area above the can.
Diffuse light curtains, with continuous sensing ability, are known in various applications. They generally utilize diverging or scanning beam, infrared emitters and photodetectors to create continuous zones of detection by sensing reflected emissions from intruding objects. Emissions may be pulsed at a fixed frequency, and electronic and logic circuitry so configured, so as to filter out all received radiation not at the emitter frequency. This curtails false triggerings, as well as variations in detector sensitivity caused by fluctuations in ambient lighting conditions.
Light curtains have been used in industry to create safety zones around operating machinery that initiate immediate shutdown signals, or other safety protocols, when the zones are transgressed. Other applications include detection systems for sensing moving objects on a conveyor belt or breaks in fabric in textile manufacturing machines. Light curtain detection systems have also been employed for monitoring passing vehicles on traffic thoroughfares. Intruder alarm systems, used in various security applications, have also utilized light curtains for defining detection zones. Another application is the use of light curtains to control automatic, pedestrian doors when prescribed zones around the doors are entered.
Light curtains have been developed that utilize both diverging and non-diverging, or collimated, beampaths. It is conceivable that technology developed for other light curtain applications may be applied towards developing the light curtain configuration required for an improved automatic waste container. However, known light curtain technology has several drawbacks when considered for this application.
Even where light curtains are collimated to create planar detection zones, no provision is described in the prior art for creating a single, continuous light curtain circumscribing a prescribed area.
Multiple, planar light curtains may be combined to create a polygonal boundary, but this can only approximate curved, non-polygonal perimeters. Additionally, the cost and complexity of combining multiple light curtains created by prior art technology to enclose a defined area is prohibitive when considered for the current goal of creating an inexpensive, automatic waste container.
Thus it is desirable to create a low-cost, robust, reliable detection system suitable for use in connection with automatically-actuated containers, such as waste containers.
The current invention describes a system for creating a continuous, collimated detection zone for an automatically-actuated device or container, such as an automatic waste container, wherein the detection zone can be made to match the opening periphery of the container, is height adjustable, immune from ambient light fluctuations and relatively simple and inexpensive to produce. Though numerous types and arrangements of automatic doors may be used, one configuration is described herein that utilizes flexible, sliding doors that minimize system complexity and volume of space required for operation.
A detection system in accordance with the invention includes a vertical, collimated, continuous light curtain of emitted infrared pulses that circumscribes the container opening. Infrared-sensitive phototransistors, mounted in locations around the container rim surface, detect reflections of emitted radiation from the surfaces of objects passing through the light curtain. The detectors may also be located subsurface, and have associated lens elements to concentrate infrared reflections onto them. Spurious detections due to ambient light fluctuations are minimized by electronic circuitry that filters out all received radiation not at the emitted frequency. The effective height of the detection zone is adjustable by varying the emitted radiation intensity and/or detector sensitivity.
It will be appreciated that in pulsed-emission embodiments, known forms of electronic circuitry could be used to identify when any of the output states of the detectors has an amplitude variation greater than a defined threshold level and a frequency substantially identical to the pulse frequency of the light-emitting sources.
The circumscribing light curtain is created by a plurality of infrared LED emitters, or by other means, such as multiple light-emitting sources created by one or more emitters and an optical fiber transmission system that delivers source emissions at desired locations. The emitters are situated below the top surface of the rim, in a channel circumscribing the container opening. A multi-lens, transparent, plastic ring is placed into the channel, above the emitters. The bottom surface of the ring (facing the emitters) is comprised of a series of lenses, one for each emitter.
Each emitter transmits infrared radiation to only one of the ring""s lenses. Molded-in, opaque, non-reflective walls in the housing segregate each emitter/lens pair into individual sections, and block infrared emissions from being transmitted to, or received from, other emitter sections. Each lens has an emitter situated at its focus, such that all emitted light impingent on the lens is refracted into a collimated, vertical light beam.
The top surface of the ring is planar and oriented with its surface normal pointed vertically. The vertical, collimated light refracted by the lenses strikes the horizontal top surface at right angles, and so continues through unrefracted, in a vertical direction.
The multiple, collimated, light curtain segments (one segment for each emitter) are joined end to end by the fixed configuration of the ring, and arranged so as to form a continuous light curtain (i.e., detection zone), fully circumscribing the can opening and extending vertically upward according to the maximum detection height set by the adjustable system sensitivity control.
A second embodiment of the ring allows for a non-horizontal top surface so the ring surface can follow the surrounding contour of the container rim, which may vary in the vertical dimension (as viewed in cross-section). In this case, each lens segment and emitter pair would be oriented so that the collimated light from the lens strikes the top surface at the required angle so as to cause refraction of the output light in a vertical direction.
A third embodiment of the ring provides a secondary, circumscribing light curtain around the container opening, in addition to the primary, vertical light curtain. In this embodiment, the ring""s top surface is comprised of two circumscribing surfaces, each receiving a portion of the collimated light refracted from the lower lens surfaces. The primary surface is oriented, as described above, to create a collimated, vertical light curtain around the container opening. The secondary surface is oriented such that the light from the lower lenses strikes at a prescribed angle, thereby refracting inwards, towards the container opening, at a given angle to vertical.
The secondary, inwardly-angled, light curtain provides additional detection coverage within the outer light curtain""s interior to illuminate and detect objects that may enter the interior of the detection zone via a path above the maximum height of the outer, vertical light curtain before dropping into the interior zone. The secondary light curtain is angled such that at maximum emitter output and detector sensitivity, the detection zone thus created does not extend beyond the vertical boundary of the primary light curtain.
The ring is a relatively inexpensive, unitary, molded plastic part that contains all lens elements and emitting surfaces in fixed orientations relative to each other, thereby obviating the need for multiple, precision optical components and/or individual adjustment of the optics to create a continuous, uniform light curtain surrounding the prescribed area.
A fourth embodiment of the ring adapts the concepts described in the previous embodiments to define a detection zone that only partially circumscribes an enclosed area. In some applications, waste containers may be partially recessed into walls or situated with one side flush against a wall, so that only a portion of the container rim protrudes beyond the wall surface. These configurations only require a detection zone that extends from that portion of the rim that is exposed beyond the wall surfacexe2x80x94i.e., the physical barrier of the contiguous wall obligates all incoming objects to pass over the exposed rim before gaining access to the container opening. Furthermore, the adjoining wall structure might be configured such that it would interfere with the detection zone if the zone were to completely circumscribe the container opening. Reflections of emitted radiation from the wall may make it difficult to achieve optimum detection sensitivity while simultaneously avoiding false triggerings.
To create a partially circumferential detection zone, the ring itself would be partial and would only match the profile of the exposed portion of the rim. The lenses and top surface(s) of the partial ring would be configured as described above, in conjunction with properly oriented emitters and opaque separator walls, to create the desired light curtain(s). The light curtain(s) would then only emanate from the exposed rim section, yet provide full coverage for all objects entering the container.
Another aspect of the invention comprises a waste container with an upward-facing opening (though the same principles described herein may be applied to openings at any given orientation). The doors covering the opening may be configured, driven and guided in many ways according to known art. In the preferred embodiment, the opening has motor-driven, flexible doors that slide together to seal off the opening or are driven to separate in order to gain access to the container interior. The doors can be constructed from flexible, molded plastic material and have a series of drive engagement features, such as gear teeth, formed into one surface. Drive motors are mounted within the container housing module. Pinions mounted on the drive motors mesh with the doors"" gear teeth, thereby providing engagement for the motors to drive the doors in either direction. The doors are deflected by guide elements and directed vertically downward along the sides of the can, thereby minimizing the can""s operating footprint. Alternative guide paths that minimize operational volume may also be used, such as curved trajectories that direct the flexible doors into spiral, winding patterns. Actuation of opening and closing operations of the door motors is controlled by electronic and logic circuitry, in conjunction with object-detecting signals received from the detection system.
In order to facilitate the tossing of refuse into the container, the doors may be driven at high speed, so they open before incoming objects would otherwise make contact. To minimize the power draw of the motors during high accelerations, elastic spring elements can be utilized to provide additional motive energy. The spring elements are deformed to store energy during the door-closing phase, when the doors are driven at slower speeds and power draw of the motors is lower. One or more controllable clutches are required to restrain the spring elements and prevent the dissipation of stored energy prematurely.
Upon initiation of the door-opening phase, the clutches are released and the spring elements are free to unwind or decompress. The springs are mechanically coupled directly with the doors, or with the door drive systems, to augment the motive energy supplied by the motors and accelerate the doors at higher rates.
The spring elements may take a variety of forms, such as coil wire compression springs, that are linearly compressed during closing via direct mechanical coupling means with the doors. Alternatively, torsion springs may be used by grounding one end to the fixed housing and the other end to the motor shaft. Closing rotations of the motor shaft winds the spring to store energy. An electromechanical clutch, also grounded to the housing and coupled with the motor shaft, restrains the motor shaft during the door-closed phase, thereby preventing the torsion spring from unwinding. During door opening, the clutch releases the motor shaft and the torsion spring uncoils to release its energy and drive the motor shaft.
Appropriate emitters and detectors can be utilized to create detection zones comprised of forms of radiated energy other than infrared light (e.g., electromagnetic radiation at other wavelengths). Additionally, the detection zones described herein may be readily adapted to other applications besides an automatic waste container. Detection zones bounding other perimeters, such as automatic water fountain rims, automatic doors for pet self-feeding or waste disposal systems, and various industrial and security applications requiring controlled perimeter sensing around defined areas, may be created utilizing the aforementioned technology adapted to the specific configuration and requirements of the target system.
Thus, one aspect of the invention is a system for detecting objects within one or more defined volumes of space, the system including a plurality of light-emitting sources, an optical element for directing emitted light from the light-emitting sources to be transmitted within, and emitted from one or more surfaces of, the optical element into a plurality of zones of substantially collimated light, the zones having a combined profile of emission from the emitting surfaces of the optical element that fully or partially encloses a defined area, with at least two of the profiles of emission being non-linear in relation to each other, the plurality of zones being substantially joined end to end, thereby combining to define one or more substantially continuous volumes of space, or detection zones, fully or partially surrounding, and extending outwards from, the perimeter of the defined area, whereby objects within the detection zones are illuminated by portions of the emitted light, and whereby portions of the light illuminating the objects are reflected from the surfaces of said objects, and at least one detector sensitive to the reflected light is situated in locations proximate to the defined area, whereby portions of the reflected light from the objects illuminate said detectors, the detectors having output states that vary in response to the illumination of the detector by the reflected light.
Another aspect of the invention includes a plurality of primary optical surfaces composed of discrete portions of the surface area of the optical element wherein each of the primary optical surfaces has a focal point with one of the light-emitting sources substantially located at the focal point, whereby that portion of the emitted light from the light-emitting source that strikes the primary optical surface is refracted into a substantially collimated beam of light, wherein each of the collimated beams is transmitted within the optical element to one or more of the emitting surfaces of the optical element.
In one aspect of the invention, at least one of the emitting surfaces is situated at right angles to one of the collimated beams within the refractive element, and the collimated beam falls incident upon the emitting surface at right angles, whereby the collimated beam continues at right angles to the emitting surface upon exiting. In another aspect, at least one of the emitting surfaces is situated at a non-normal angle to one of the collimated beams within the optical element and the collimated beam falls incident upon the emitting surface at a non-normal angle, thereby being refracted upon exiting the emitting surface into a collimated beam at a defined angle to the emitting surface. In a further aspect, the light-emitting sources receive light energy from one or more remote, primary sources via an optical fiber transmission system. In another aspect, each of the light-emitting sources emits light to only one of the primary optical surfaces, and the light-emitting sources are located substantially at the focal points of the primary optical surfaces. In still another aspect of the invention, each of the light-emitting sources emits light to a plurality of the primary optical surfaces, which share a common focal point; the light-emitting source is located substantially at the common focal point; and each of the primary optical surfaces that receives light from one of the light-emitting sources is comprised of non-contiguous ones of the primary optical surfaces.
The system also can include physical boundary walls, substantially opaque to, and non-reflective of, light emitted from the light-emitting sources, and the boundary walls are configured so as to prevent illumination of the primary optical surfaces by any of the light-emitting sources that are not located substantially at the focal points of the primary optical surfaces.
The invention can include electrical control elements for pulsing the emitted light from the light-emitting sources at a defined frequency, and electrical circuitry for identifying when any of the output states of the detectors has an amplitude variation greater than a defined threshold level and a frequency substantially identical to the pulse frequency of the light-emitting sources.
In one practice of the invention there is a maximum distance from the emitting surfaces of the optical element at which reflections of the emitted light from objects within the detection zones illuminate the detectors with sufficient radiant energy to cause at least one of the output state levels of the detectors to be greater than the threshold level. In this case, the system will include electrical circuitry for identifying when any of the output states of the detectors has an amplitude greater than the threshold level, and electrical control elements for adjusting the maximum distance by varying the amplitude of light energy emitted by the light-emitting sources (or for adjusting the distance by varying the set value of the threshold level).
The invention can also be embodied in a container including an opening through which objects are inserted into the interior space of the container, one or more movable doors that close to substantially cover the opening and open to expose the opening of the container, elements for detecting objects within one or more volumes of space, such volumes of space having (1) base profiles proximate to, and partially or fully surrounding, the opening, and (2) substantially parallel sides extending outwards from the base profiles in a direction of increasing distance from the container. Electrical control and electromechanical motive elements are provided for causing the doors to open when objects are detected within such volumes of space. In another aspect, such containers can include the systems described above, thus creating volumes of space for detecting objects.
A container according to the invention can also include spring elements and mechanical coupling elements arranged so that the spring elements deform and store elastic energy during the closing motion of the doors, and then controllably release the stored energy to provide motive energy to drive the doors open. Electrical control elements can be provided for causing the electromechanical motive elements to close the doors after a set time period (which can be adjusted) during which the output levels of the detectors are less than the threshold level (i.e., corresponding to non-detection of objects in the detection space).
The container can also include guide elements to direct the flexible doors to deform when opening and closing, whereby the doors are guided into configurations proximate to one or more of the sidewalls of the container when in the open position. The door elements may include drive engagement surfaces that engage drive engagement surfaces of motors or other drive elements, to generate and apply forces to cause the doors to move.
Finally, the container may also include detector elements for detecting one or more defined positions of the doors, a first electrical control module for regulating a mechanical motive means for driving the doors according to the output states of the detectors; indicators providing a visible or audible signal for indicating when at least one of the output states of the detectors exceeds a threshold level, and a second electrical control module for setting modes of operation of the doors. Such modes may include a mode wherein the doors open in response to the output state of at least one of the detectors exceeding said threshold level; a mode wherein the doors remain in an open position irrespective of output state of the detectors; and a mode wherein the doors remain in a closed position irrespective of output states of the detectors.